Experimental techniques for optical frequency metrology

In the framework of this thesis, I present recent activities in the Laboratoire Temps-Fréquence (LTF) of the University of Neuchâtel, concerning the optical frequency metrology group. We developed the frequency discriminator technique for the characterization of the narrow linewidth heterodyne optical beats. The examination of the four different types of the frequency and phase discriminators has identified the appropriate tools for the analysis of the low-noise signals. We made the experimental test of the β-separation line formalism that enables easy calculation of the laser linewidth from its frequency noise power spectral density (PSD). Earlier proposed geometrical approximation has been validated in a wide linewidth range and for different laser line shapes. We developed and characterized the second ultra-stable high-finesse Perot-Fabry passive reference cavity. A novel low-noise planar waveguide extended cavity laser (PW-ECL) has been stabilized to this reference cavity in a Pound-Drever-Hall stabilization scheme. A thermal model of the cavity enclosure has been made and based on that an improvement in the temperature control system was possible, resulting in the higher flexibility of the cavity temperature change. Finally, the noise properties of a novel type of the ultrafast optical frequency comb were examined. A diode-pumped solid-state laser (DPSSL) Er:Yb:glass (ERGO) frequency comb is proven to be capable of the coherent frequency division from optical to microwave, at the level of stability of 10^-15 at 1 s. It is shown that the dynamics of the carrier-envelope offset (CEO) beat plays an important role in the stabilization of this type of the ultrafast laser.

Thèse de doctorat : Université de Neuchâtel, 2014